Effects of combined action of serum interferon alpha and interleukin-6 from systemic lupus erythematosus patients on the differentiation and maturation of dendritic cells derived from hematopoietic precursor cells / 中国组织工程研究

ABSTRACT

BACKGROUND:Systemic erythematosus lupus (SLE) is closely associated with activity of dendritic cells (DCs) function.DCs derive from hematopoietic precursor cells (HPCs) in vivo and many factors might affect the differentiation and maturation of DCs.The cytokine network was in disturbance and the levels of various cytokines were anomalous in SLE serum.Previous studies mainly addressed effects of single factors.OBJECTIVE:To investigate the effects of joint action of serum interferon (IFN)-α and interieukin (IL)-6 in the serum of SLE patients on the differentiation and maturation of DCs derived from CD34~+ HPCs.DESIGN,TIME AND SETTING:The grouping,controlled and completely random designed study was performed at the Department of Microbiology and Immunology,Nanjing Medical University from May 2006 to October 2008.MATERIALSPeripheral blood samples were collected from 50 SLE patients from the Department of Rheumatology,First Affiliated Hospital of Nanjing Medical University and 30 healthy volunteers from Nanjing Medical University.Cord blood samples were collected from 15 full-term normal delivery neonates from Nanjing Maternity and Children Health Care Hospital Affiliated to Nanjing Medical University.Informed consent was obtained from all patients and their family members.METHODS:Peripheral blood samples were collected from SLE patients and healthy volunteers.According to serum IFN-α and IL-6 concentrations of normal person,95% reference value range of serum IFN-α and IL-6 concentrations were calculated by the method of percentiles.Above this range represented abnormal increase.Cord blood mononuclear cells were harvested by Ficoll-Hypaque density gradient centrifugation.CD34~+HPCs were purified from cord blood by magnetic cell sorting system (MACS),and cultured to differentiate to DCs.There were 6 groups in this study.Normal serum,SLE serum with elevated levels of IFN-α,SLE serum with elevated levels of IL-6,SLE serum with elevated levels of IFN-α and IL-6,SLE serum with anti-IFN-α and anti-IL-6 neutralizing antibodies,or normal serum with exogenous IFN-α and IL-6 were respectively added to the culture medium in each group.10% volume fraction serum was used in each group,for totally 14 days incubation.MAIN OUTCOME MEASURES:The phenotype of DCs was analyzed by flow cytometry (FCM).Cytokine production was assessed by ELISA.The capacity of DCs to stimulate allogenic T lymphocyte proliferation and to regulate T cell differentiation was evaluated in a mixed lymphocyte reaction (MLR).RESULTS:Compared with normal serum,HLA-DR,CD80 and CD86 expression was significantly increased in the medium containing SLE serum with elevated levels of IFN-α,SLE serum with elevated levels of IL-6,SLE serum with elevated levels of IFN-α and IL-6 and normal serum with exogenous IFN-α and IL-6 (P＜0.05),whereas IL-12 levels were significantly decreased (P＜0.05),and capacity of DCs to stimulate allogenic T lymphocyte proliferation was significantly enhanced (P＜0.05).Above-mentioned indexes recovered to a normal level in the medium containing SLE serum with anti-IFN-α and anti-IL-6 neutralizing antibodies.Compared with normal serum,proportion of both CD3~+CD8~-IFN-γ~+ and CD3~+CD8~+IFN-γ~+ T cell subsets was significantly reduced in the medium containing SLE serum with elevated levels of IL-6 (P＜0.05).However,proportion of both CD3~+CD8~-IFN-γ~+ and CD3~+CD8~+IFN-γ~+ T cell subsets was significantly increased in the medium containing SLE serum with elevated levels Of IFN-α,SLE serum with elevated levels of IFN-α and IL-6,normal serum with exogenous IFN-α and IL-6 (P＜0.05).CONCLUSION:The joint action of IFN-α and IL-6 in SLE serum promotes the differentiation and maturation of DCs derived from CD34+HPCs and affects the DC-mediated T cell differentiation,which might contribute to the pathogenesis of SLE.